Tickless PET range test measurement by TraqLabs Test setup
Test results
The range test method and test setup was conducted in the figure shown above. The distance between the range tester device and the TickLess Pet was 1.5 �. The oscilloscope measured the product’s transmitter with 2 probes and the range tester device’s receiver also with 1 probe.
Theory The transmitter’s datasheet mentions that the sound pressure level (SPL) is 120 đ?‘‘đ??ľ for 10 đ?‘‰ at 30 đ?‘?đ?‘š distance. It does not spicifically state that this is a sine wave, but this type of measure use sine. The product use 6 đ?‘‰ square wave to drive the transmitter, so the đ?‘‰ value of this signal is 3 đ?‘‰ . The SPL at this voltage is:
The yellow signal is the receiver’s positive terminal, the blue and purple signal is the TickLess Pet’s transmitter positive and negative terminals. The time delay beetween the transmitter and receiver signal was 4.3 đ?‘šđ?‘ . In 25°đ??ś air the speed of sound is 346.2 , so the distance was 346.2 ∗ 4.3 ∗ 10 between the product and range tester.
đ?‘ = 1.49 đ?‘š
3� 10�
đ?‘†đ?‘ƒđ??ż
= 120 đ?‘‘đ??ľ − 20 ∗ lg
đ?‘†đ?‘ƒđ??ż
= 109.54 đ?‘‘đ??ľ at 30 cm distance
This SPL is referring to 30 đ?‘?đ?‘š, but the measurement device is tested for 1.5 đ?‘š, so the SPL regarding this distance is: đ?‘†đ?‘ƒđ??ż
= 109.54 đ?‘‘đ??ľ − 20 ∗ lg
.
đ?‘†đ?‘ƒđ??ż
.
30 đ?‘?đ?‘š 1.5 đ?‘š
= 95.56 đ?‘‘đ??ľ at 1.5 đ?‘š distance
The measurement device receiver’s sensitivity is −68 đ?‘‘đ??ľ in the worst-case scenario. This means the „link budgetâ€? decreases with this value. The rest of the SPL is: 95.56 đ?‘‘đ??ľ − 68 đ?‘‘đ??ľ = đ?&#x;?đ?&#x;•. đ?&#x;“đ?&#x;” đ?’…đ?‘Š In free air, the sound level will decrease by 6 đ?‘‘đ??ľ every time the distance to the transmitter doubled. This means, the measuring device theoretically will measure the product range up to: |
đ?‘&#x; = 1.5 đ?‘š ∗ 10
.
|
= 35.8 đ?‘š
The transmitted and received signal frequency was 40 đ?‘˜đ??ťđ?‘§. The received signal đ?‘‰ = 13.1 đ?‘šđ?‘‰, which means that the „link budgetâ€? is: đ?‘†đ?‘ƒđ??ż
= 20 ∗ lg
13.1 ∗ 10 đ?‘‰ 3đ?‘‰
+ 68 đ?‘‘đ??ľ = đ?&#x;?đ?&#x;Ž. đ?&#x;– đ?’…đ?‘Š
Theoretical value (đ?&#x;?đ?&#x;•. đ?&#x;“đ?&#x;” đ?’…đ?‘Š) and measured value (đ?&#x;?đ?&#x;Ž. đ?&#x;– đ?’…đ?‘Š) has a slight difference. It is likely that this is caused by the product’s housing.
Conclusion The product is capable of broadcasting the ultrasonic pulses well over the 1.5 đ?‘š distance with a minimum battery life of a year.